The present invention is directed to signal converter circuits such as voltage converter circuits. By way of example and not by way of limitation, an exemplary signal converter circuit will be described that employs a first upper switch to periodically couple a circuit node with a supply voltage, and employs a second lower switch to periodically couple the circuit node with a lower potential than the supply voltage. Sometimes the lower potential is at ground potential. In such circuits the output signal is presented from the circuit node via a delaying circuit, usually embodied in a filtering circuit.
In a fault condition where one of the switches fails in a closed orientation the output signal achieve an over-voltage condition at which output potential can damage connected equipment. If one could predict the onset of an over-voltage condition, measures may be timely taken to prevent damage to connected equipment.
There is a need for an apparatus and method for indicating onset of a high-voltage at an output locus of a pulsed signal supply.